Trick thefts are a growing danger, and especially elderly people are often defenseless against the audacity of uninvited visitors. A door viewer is therefore a basic requirement for your decision about whom to open the door to and whom to keep out. ABUS door viewers are characterized by wide-angle optics, ensuring you can see who is standing at your door. The extension piece for the ABUS door viewers 1200, 2200, 2203, and 2300 is used whenever the door is thicker than 53 mm. An extension piece covers an additional 10-17 mm of door thickness. You can also use multiple extensions in succession; however, the viewing angle decreases with increasing length.